to apps/myapp/handlers/add.php and apps/myapp/handlers/edit.php. Without the jquery-ui I got the javascript errors TypeError: $.datepicker is undefined and TypeError: $(...).datepicker is not a function

I'd submit a pull request but I'm not sure if it makes more sense to add them to admin/handlers/util/datewidget.php or to cli/views/crud-app/types/date.html and cli/views/crud-app/types/datetime.html or somewhere else.